This invention relates to knitted fabrics, and more particularly, to a novel construction for knitted stockings.
There are two main knitting processes used to make knitted fabrics: tubular or circular forms, which usually employ filling or weft knits; and flat forms, which usually use warp knits. Seamless hosiery is produced by circular knitting machines, as is known in the art. In making seamless hosiery, knitting in a tubular or circular form is the method of choice for socks and stockings because there is no seam requirement inherent in circular knitting, and the method gives high speed, economy of manufacture and high quality. The circular knitting method also allows for use of a wide variety of needle gauges and spacings, from coarse ("heavy" or "athletic" type) gauges to very fine gauges used in fine hosiery such as women's stockings.
Most modern circular hosiery machines use 31/2 or 4 inch diameter needle cylinders. They employ double hooked latch needles that work directly opposite one another in substantially the same plane to knit [1] the leg portion; [2] the main foot portion; [3] the heel; [4] the toe. Heels and toes are often left open and later closed in a separate step. Usually the seam establishing the toe box is positioned above the toes, but a Getaz toe may be used instead, providing a seam under the toes, as is known in the art. The number of needles used in the needle cylinders may vary. Heavyweight coarse socks may be knitted using 80-120 needles per cylinder, often with terry loops or other techniques used to provide cushioning in the sole of the foot. Medium weight "dress" socks may use 120-240 needles, often with a rib-knit construction to improve comfort and moisture wicking. Sheer stockings and related products like panty hose use very fine needles, as high as 400 for a 3 1/2 inch diameter needle cylinder.
In flat bed knitting machines, needles are either mounted on a flat plate or needle bed or in two beds that are at right angles to one another, and typically each at a 45.degree. angle with respect to the horizontal. The fabric to be knitted passes down through the space between the plates where cam operated needles knit in synchrony With the actions of yarn guides, as is known in the art. The width of the resultant fabric can be easily varied by changing the number of active needles. This allows not only tapering but also shaping of fabrics, which when sewn together make a complete garment. An almost unlimited variety of designs is possible by changing yarn color, stitch type, cam profiles, and Jacquard devices. Cotton frames on these machines allow for automatic narrowing and widening devices.
Recently, new leisure and sport sock designs have combined two elements: light or fine needle foot portions for comfort (e.g., thin silk, cotton or nylon), with heavy knit coarse lower leg portions to provide warmth, ankle/lower leg protection and a stylish appearance. In these new designs, a heavy circular knit lower leg portion is sewn or joined with a thin or fine circular knit foot portion. Some of these new designs use drawstrings, pockets and other value added features to enhance their stylishness and utility for a number of situations, from snow skiing and mountain climbing to lower leg leisure wear.
Although these new designs have become very popular and have started a new paradigm in the leisure sock industry, limitations inherent to circular knitting processes used in hosiery make it difficult go further to satisfy recent consumer tastes and desires:
[1] Up to now, it has been very difficult and expensive or virtually impossible to vary the diameter of a circular knit article, so the foot portion and leg portion are respectively confined to a set diameter along their respective lengths. In short, it is not possible without undue expense and extra processing steps to vary the diameter of the lower leg portion to create a tapered lower leg. Tapered lower legs are desirable from a style standpoint and offer physical advantages as well. A tapered lower leg allows a self supporting stance for a heavy knit material, reducing the need for a elastic material or a biased elastic design that socks typically use to keep the sock from falling down. Not having the elasticity improves circulation and eliminates the problem of generating marks and depressions on the flesh of the wearer. This self supporting stance can be aided by having the lower part of the lower leg portion rest on the wearer's shoe. A tapered lower leg design also allows for insertion of pant or pantyhose legs into the sock without difficulty. Moreover, a tapered lower leg offers an attractive "draped" appearance not found in circular knit articles. PA1 [2] It has also been difficult or impossible to provide for complex patterns for the lower leg. Consumers have expressed interest in having pattern differentiation where different yarns, needle patterns, colors, or even fabric heights are used in the lower leg portion.
Circular knitting machines are not capable of providing for both substantially tapered width sock bodies and performing complex knitting steps and yarn changes required for beautiful complex lower leg patterns. As a result, products in this market segment are attractive but cannot be substantially tapered and have complex Jacquard style patterning. Even double cylinder Jacquard Link machines used in the Orient have similar limitations in that, barring expensive additional steps, they can only produce traditional sock sizing, with no substantial taper of the sock body. They are also often limited to finer gauge yarns.
One stocking shown in the prior art is U.S. Pat. No. 5,035,008 to Schneider. This leisure wear stocking shows a lower leg portion of heavy cotton circular knit material sewn or joined to a thin silk material with a reinforced toe or heel used for a foot portion. While this alleviates the problems associated with uniform thick Socks like bunching and excessive perspiration of the foot, Schneider does not provide for a substantially tapered lower leg whose advantages are cited above, and is subject to the limitations of circular knitting machines as cited above.
U.S. Pat. No. 560,831 to Barroll shows an example of the early legging art where the leg portion terminates in a strap structure that the wearer steps into. The lower leg portion used for the legging is the result of a circular knitting process and lacks substantial taper and is similarly subject to limitations of circular knitting machines.
U.S. Pat. No. 1,708,342 to J. H. Vogt shows a stocking that combines circular knitting methods for the "tubular" lower leg and foot portions of the sock with straight or flat knitting methods used for the foot bottom, heel and toe. It also does not provide taper or design freedom for the lower leg portion as is contemplated above.
Similarly, U.S. Pat. No. 2,125,451 to Kolliner shows a "breechette" with no foot structure. All components are tubular or circular knit and no taper is provided.
It is therefore one object of this invention to provide for a tapered lower leg sock portion that can be combined with the advantages of using light or fine circular knit fabrics for the foot portion.
It is another object of this invention to provide a lower leg portion knitting process that satisfies the requirements of a tapered lower leg portion and allows full use of complex multi-differentiated patterning as well.